House-dust mites (Dermatophagoides spp.) are closely associated with man, prevailing at high densities in a variety of niches in human dwellings. Their numbers are exceptionally high in dust collected from bedding items, floors under beds, sofas, couches, and other furnishings. These mites constitute by far the most abundant fauna found in modern homes. They have recently been proven to produce allergens causing bronchial asthma and rhinitis in house-dust sensitive individuals. Physicians and patients are in need of preventive and curative measures for mite infestations in homes.